The presence and use of personal computers in all phases of business and the home is now well established. Also, now well established are a myriad of problems ranging from vandalism, including the introduction of computer viruses into computer operating systems and programs, to theft or alteration of sensitive business information and data. Great damage occurs when diskettes containing sensitive data, both business and personal, are compromised. This need occasioned the introduction of physical security adjuncts such as internal locking systems and external disk drive locking devices such as that embodied in U.S. Letters Pat. No. 4,685,312, owned by Applicant.